$\mathrm{N}\mathrm{a}\mathrm{B}{\mathrm{H}}_4$ is a weak reducing reagent. So it reduces only carbonyl group while reduction of -COOH group does not happen and it remains unaffected. $\mathrm{L}\mathrm{i}\mathrm{A}\mathrm{l}{\mathrm{H}}_4$ is strong reducing reagent; so it can reduce both carbonyl and carboxylic groups.